A major progress in abdominal surgery has occurred during the last decades with the introduction of laparoscopic and minimally invasive techniques. These innovative procedures focused much attention due to their several advantages: smaller abdominal incisions needed, resulting in faster recovery of the patient, improved cosmetics, and shorter stay in the hospital. The safety, efficiency and cost-effectiveness of laparoscopic surgery have subsequently been demonstrated in clinical trials for many routine abdominal operations. However, from the surgeon's point of view, there are still many difficulties in learning and performing such procedures with current laparoscopic equipment, which is non-ergonomic, non-intuitive and missing in adequate stiffness, precision and force feedback.
In order to overcome the disadvantages of traditional minimally invasive surgery (MIS), robot technology has been introduced into the operation room. Although a wide range of diagnostic and therapeutic robotic devices have been developed, the only commercial systems that have already been used in human surgery are the da Vinci System, by Intuitive Surgical, [Guthart2000], and ZEUS, by Computer Motion. Following the fusion between the two companies, the ZEUS robot is no longer produced. The major advantages of these robotic systems are related with the additional degrees of freedom available to the surgeon that allows more complex movements in a limited space, with an increased stiffness. This increased mobility and stiffness has led to short learning curves even for non-laparoscopic surgeons. A major disadvantage of these systems is the high cost of acquisition and maintenance which are actually not affordable for the majority of surgical departments worldwide.
Another drawback of these systems is related with the fact that current surgical robots are voluminous, competing for precious space within the operating room environment and significantly increasing preparation time. Access to the patient is thus impaired and this raises safety concerns. In addition, although robotic systems offer excellent vision and precise tissue manipulation within a defined area, they are limited in operations involving more than one quadrant of the abdomen. Since many gastrointestinal operations involve operating in at least two abdominal quadrants, the repeated disconnection and movement of the robots increase significantly the duration of the surgical procedure.
Despite various existing interesting systems and after several years of surgical instrumentation research, surgical robotics is still only at the very beginning of a very promising large scale development. One of the major open drawbacks is related to the fact that current robotic instruments are still too bulky and have insufficient dexterity for complex surgical procedures.
Further weaknesses of these systems are related with the stiffness, precision and payload capacity of the micro-manipulator units. A large number of conventional and robotic manipulators have been developed [Taylor1999, Cavusoglu1999, Mitsuishi2003, Mayer2004, Guthart2000, Tavakoli2003, Seibold2005, Das1997, Dachs2006, Abbott2007, Ikuta2003, Nakamura2000, Yamashita2005, Arata2005, Salle2004, Kobayashi2002, Dario2000, Peirs2003, Simaan2004, Ikuta2003, Focacci2007, Ishii2007] but their size, dexterity, stiffness, precision and payload capacity are not completely fulfilling the needs for MIS. In some cases, these insufficiencies lead to increased operative time or imprecise performance of several surgical tasks.
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